Alkali metal aliphatic and aromatic hydrocarbon acetals and ketals and their use as polymerization initiators, etc.

ABSTRACT

Alkali metal aliphatic and aromatic hydrocarbon acetals and ketals are initiators for the polymerization of conjugated dienes and copolymerization of conjugated diene and vinyl monomers. Mono-acetal and mono-ketal polymers are produced by termination of the foregoing polymers and copolymers with methanol, isopropanol, etc.; diacetal and diketal polymers are produced by terminating said polymers and copolymers with a joining agent, e.g., Cl2Si(CH3)2; and polyacetal and polyketal polymers and copolymers are produced by terminating said polymers and copolymers with a polyfunctional joining agent, e.g., Cl3SICH3. Other mono-acetal and mono-ketal polymers are prepared by terminating said polymers and copolymers with ethylene oxide or carbon dioxide. The terminally reactive acetal polymers can be converted to other useful polymeric products. For example, terminal primary hydroxy polymers are produced by hydrolyzing the foregoing acetal and ketal polymers and copolymers with dichloroacetic acid catalyst in toluene:water mixtures. Terminal monohydroxy polymers are produced by hydrolyzing polymers and copolymers terminated at one end with an acetal or ketal group. Terminal dihydroxy polymers are produced by (a) hydrolyzing polymers and copolymers terminated at one end by an acetal or ketal group and with a hydroxy group at the other terminal or (b) by hydrolyzing diacetal or diketal polymers. Terminal trihydroxy (polyhydroxy) polymers are formed by hydrolyzing triacetal or triketal (polyacetal or polyketal) polymers. Hydrolyzed acetal or ketal polymers (especially di-and tri-functional) are converted by suitable chain-extension processes (e.g., by polymerization or copolymerization) to give sulfur-curable elastomers.

United States Patent 1 Halasa et al.

[4 1 Jan. 21, 1975 [73] Assignee: The Firestone Tire & Rubber Company, Akron, Ohio [22] Filed: Dec. 13, 1972 [21] Appl. No.: 314,876

Primary Examiner-William F. Hamrock [57] ABSTRACT Alkali metal aliphatic and aromatic hydrocarbon acetals and ketals are initiators for the polymerization of conjugated dienes and copolymerization of conjugated diene and vinyl monomers. Mono-acetal and monoketal polymers are produced by termination of the foregoing polymers and copolymers with methanol. isopropanol, etc.; diacetal and diketal polymers are produced by terminating said polymers and copolymers with a joining agent, e.g., CI Si'(CH and polyacetal and polyketal polymers and copolymers are produced by terminating said polymers and copolymers with a polyfunctional joining agent, e.g., Cl SlCH Other mono-acetal and mono-ketal polymers are prepared by terminating said polymers and copolymers with ethylene oxide or carbon dioxide. The terminally reactive acetal polymers can be converted to other useful polymeric products. For example, terminal primary hydroxy polymers are produced by hydrolyzing the foregoing acetal and ketal polymers and copolymers with dichloroacetic acid catalyst in toluenezwater mixtures.

Terminal monohydroxy polymers are produced by hydrolyzing polymers and copolymers terminated at one end with an acetal or ketal group. Terminal dihydroxy polymers are produced by (a) hydrolyzing polymers and copolymers terminated at one end by an acetal or ketal group and with a hydroxy group at the other terminal or (b) by hydrolyzing diacetal or diketal polymers. Terminal trihydroxy (polyhydroxy) polymers are formed by hydrolyzing triacetal or triketal (polyacetal or polyketal) polymers. Hydrolyzed acetal or ketal polymers (especially'di-and tri-functional) are converted by suitable chain-extension processes (e.g., by polymerization or copolymerization) to give sulfur-curable elastorners.

9 Claims, No Drawings ALKALI METAL ALIPHATIC AND AROMATIC HYDROCARBON ACETALS AND KETALS AND THEIRUSE AS POLYMERIZATION INITIATORS, ETC.

This invention relates to the use of alkali metal aliphatic and aromatic hydrocarbon acetals and ketals in various processes and includes new products which are produced.

The invention relates to various terminally functional polymers and processes for preparing the same. A number of different terminally reactive polymers are discussed, e.g., acetal polybutadienyl lithium polymers, monoacetal polymers, diacetal polymers, triacetal polymers, monoacetal mono-X polymers (in which X stands for any one of various chemical groups), dihydroxy polymers, trihydroxy polymers, etc. Lithiumterminated polymers are defined herein as live poly mers.

Polymers with terminal functional groups are to be distinguished from polymers with randomly functional groups. The utilization of terminal end groups on a polymer backbone enables substantially more effective cures than are possible with randomly functional polymers. Compounds which are chain-extended through terminal end groups contain no dangling chain ends to weaken the vulcanizate network. Also a greater molecular weight between crosslinks can be achieved with a terminally functional polymer than with a randomly functional polymer. Thus, by simple chain extension, liquid polymers can be increased in viscosity and even converted to solids while soft gums can be chain extended to more rigid materials.

Chain extension, as the term is used herein, broadly means increasing the molecular weight of a monomer or polymer having terminally functional groups by curing or coupling or crosslinking to produce a polymer of greater molecular weight.

The use of acetal and ketal lithium initiators assures the production of terminal functional groups in the polymers because the functionality (albeit protected functionality) is built right into the initiator itself and the initiators are incorporated as chain ends.

When the polymer backbone is a homopolymer or a copolymer of a conjugated diene containing 4 to 6 carbon atoms or a copolymer of such a conjugated diene and a vinyl monomer, there is also a capacity for further sulfur or peroxide cures of the olefinic bonds. One of the most useful ranges for terminally functional polybutadiene polymers is the molecular-weight range of 600-l0,000 because such polymers are liquid and pourable with an intrinsic viscosity of 004-10. Such polymers, whether pourable or of higher molecular weight, may be used as disclosed herein for the production of hydroxy polymers which, in turn, may be used as end products for various purposes, and are disclosed herein as intermediates for chain-extended polymers which may be used as adhesives, binders (especially for solid rocket fuels), potting compounds, caulking compounds, sealants, and also many types of molded articles. Each of the examples which follow produces such a product, the suitability for any particular use depend ing upon its molecular weight.

The processes and products to which the invention relates may be grouped as follows:

1. initiators for the polymerization and copolymerization of conjugated dienes and the copolymerization of conjugated dienes with aliphatic and aromatic vinyl monomers. The processes and the live polymers are new.

2. The production of mono-acetal and -ketal polymers and copolymers by terminating said live polymers and copolymers with alcohols, e.g., methanol, isopropanol, etc. The polymers and copolymers are new.

3. The production of diand poly-acetal and diand poly-ketal polymers and copolymers by terminating said live polymers and copolymers with a difunctional or polyfunctional joining agent; for example, CH Cl CH CI, CCl Cl Si(CH C H Br dichlorodimethyl ether, (ClCl-l .C H diisocyanates, Cl Si.CH triisocyanates, Cl CH, etc. The polymers and copolymers are new.

4. The production of monoacetal and monoke almono(X) polymers (X=R.OH,-COOH,-CSSH- ,SH, etc.) by terminating said live polymers and copolymers with anionically reactive agents, e.g., epoxides, aldehydes, ketones, carbon dioxide, carbon disulfide, sulfur, alkyl disulfides, etc., followed by treatment with a protic solvent. The polymers and copolymers and the processes are new.

5. The conversion of acetal and ketal polymers and copolymers into hydroxy polymers and copolymers.

Terminal monohydroxy polymers and copolymers are produced by hydrolyzing polymers and copolymers terminated at one end with an acetal or ketal group.

Terminal dihydroxy polymers and copolymers are produced in either of the following ways:

a. reacting one of said live acetal or ketal polymers or copolymers with an alkylene oxide such as ethylene oxide or propylene oxide, etc., and hydrolyzing the product;

b. hydrolyzing acetal Si N acetal I 3 F or ketal W S1 W ketal l Cl-l The products are new.

Terminal tri(or higher poly) hydroxy polymers are formed by hydrolyzing tri(or higher poly) acetal or tri- (or higher poly) ketal polymers and copolymers. These processes are new.

6. Chain-extending hydrolyzed terminal acetal or ketal polymers to give polyurethanes, polyesters, etc.

PRIOR ART Ethyl lithium-3-propyl acetaldehyde acetal Li (CH O(|2H .CH

, analogous to that disclosed by Eaton et al. Such compounds are represented by the following formulae:

LiR-O-C-R LiRO-C-R Acetal Ketal in which R is a branchedor straight-chain or cycloalkylcnc group of l to 20 carbon atoms or phenylene or alkyl phenylcnc in which each alkyl group contains 1 to 3 carbon atoms, and R,, R and R are straightchain or branched-chain or cycloalkyl groups of l to 3 or 5 or l0 or more carbon atoms or phenyl, or alkyl phcnyl in which each alkyl group contains 1 to 3 carbon atoms; it being understood that R, and R may be alkyl groups which are part of a ring, cg. a pyranyl group The lithium acctals and kctals, such as those disclosed hcrcin and represented by the foregoing formulae arc hydroxyl carriers and are to be distinguished from compounds having either of the following formulae:

LiR O R and LiR- ,CR

H Acetal Ketal which are carbonyl carriers. In carrying out the invention, any hydroxy carrier hydrocarbon aliphatic or aromatic acetal 0r ketal may be used. Representative compounds in which Et stands for ethyl and n l to are:

Acetals OEt Li- (aw -canon;

OCH

Li-(CH -OCHCH pcn Li-(CH -0CH l u @-ocscu OCGHS.

(mt Li- (cn -@0-cn-cn O\Et Li@-OCHCH one Li- (CH2 @Cl-l2-0-CH-CH3 Li- (CH -OQ K- (CH -aceta1 Li- (Cl-l -OTCH Na- (CH -keta1 Goldberg US. Pat. No. 3,055,952, I-Isieh US. Pat. No. 3,175,997, and S.Reed (J.Po ly. Sci.A-l, 1187, 1972) each contain an extensive discussion of preparing dihydroxy-terminated polymers by treating dilithium polymers with ethylene oxide. Undesirable gelation problems have been encountered with the procedures described there due to thickening of the solution, even at low concentration of monomer. Agitation was totally lost during the termination reaction. The high viscosity of the reaction mixtures made the processes unattractive.

British 1,029,451 discloses the use of ethers in hydroxylation of live polymers with ethylene oxide to inhibit gel formation.

According to the present invention, the use of the acetal and ketal polymers and copolymers circumvents the gelation difficulties. The solutions obtained are of low viscosity, stirrable, and can be transferred from one reactor to another without the use of high pressure, making the procedure more attractive.

EXPERIMENTAL the corresponding ketals and their preparation is obvious. Methods representative of the preparation of the acetals and ketals follow.

Reference is made, more particularly, to lithium compounds and their use, but the sodium and potassium, etc. compounds which react similarly, and their use are included.

PREPARATION OF ACETALS EXAMPLE 1 PREPARATION OF ETHYL 3-BROMOPROPYL ACETALDEHYDE ACETAL Commercial 3-bromopropanol, as received, was stirred over powdered sodium carbonate until the pH was above 5 (above 6 hours) and then stored at 30 C. over sodium carbonate until used.

Ethyl vinyl ether (212 ml, 203 g, 2.82 moles) was added to purified, non-acidic 3-bromopropanol (200 g, 1.44 moles) in a one-liter, three-necked flask equipped with a magnetic stirring bar, thermometer, and con denserwith drying tube. Dichloroacetic acid (2.00 ml) was added. The temperature rose gradually to 50 C. over an hour. An hour later l'mI. more of acid was added and again after 4 additional hours. The mixture was stirred overnight. In the morning, 8 g. of powdered sodium carbonate was added, and the mixture stirred for several hours. Filtration, removal of excess ethyl vinyl ether in vacuo, and vacuum distillation from sodium carbonate gave the required bromoacetal as a colorless liquid (bp 49-5l/1 mm, 46 g.). The ethyl 3- bromopropyl acetaldehyde acetal which wasproduce'd, was stored over powdered sodium carbonateat 30 C.

EXAMPLE 2 PREPARATION OF ETHYL 6-CHLOROHEXYL ACETALDEHYDE ACETAL Ethyl 6-chlorohexyl acetaldehyde acetal'was prepared frorn o-chlorohexanol by a procedure analogous to that outlined in Example 1. Recipe was as follows:

Cl-(CH OH 250 gms. CHFCH-OEI 270 ml. CIZCHCOOH 2.7 ml.

The reaction product,

OEt

was recovered by vacuum distillation; bp 99l0l C. at 8 mm. (376 gms.).

EXAMPLE 3 PREPARATION OF ETHYL p-IODOPI-IENOL ACETALDEHYDE ACETAL I@ 0cncn The preparation of the product follows with the substitution of p-lodophenol for 6-chlorohexanol, as in Example 2. The procedure is represented by the following OEt bromocompound.

EXAMPLE 4 PREPARATION OF ETHYL 3-BROMOPROPYL ACETONE KETAL The ethyl vinyl ether of Example I is replaced by l.- methylethenyl ethyl ether (the latter being prepared in the two-step procedure described by Henze and Muschison .I. Am.Chem. Soc. 53, 4077 (1931) for Step No. 1

(CH -T-OEt) is reacted with a halohydrin, e.g. Br--(CH -OH to form OEt by the procedure described in Example 1. The chloroderivative can be similarly prepared.

LITHIATION OF HALO ACETALS AND HALO KETALS The acetals were lithiated by the procedures illus trated below.

EXAMPLE 5 PREPARATION OF ETHYL 3-LITHIOPROPYL ACETALDEHYDE ACETAL The formula of the product is:

i z s Li (CH .O.CH.CH

A threemeck flask was charged with 200 ml. of dry diethyl ether and 0.22 g.-atoms of lithium dispersion (containing 1 percent Na). About percent of a total of 0.094 mole of ethyl 3-bromopropyl acetaldehyde acetal was added at room temperature under anhydrous and anaerobic conditions. The remaining bromoacetal was added dropwise over a one-hour period at a temperature between 0 C. and C. The mixture was stirred at 0 C. for an additional one hour and then transferred by positive argon pressure to a beverage bottle and subsequently filtered in a dry box to remove the unreacted lithium metal and the lithium 'bromide that was formed. The amber-colored filtrate was analyzed by the Gilman double titration method. (Total base 0.195 M; Free Base 0.115 M; percent C-Li 41.0 percent; Conc. C-li 0.080 M).

Essentially the same procedure was repeated in hexane solution with the following titration results (before EXAMPLE 6 PREPARATION OF ETHYL 6-LITHIOHEXYL ACETALDEHYDE ACETAL A three-neck flask wascharged with 300 ml. of dry 0 diethyl ether and 0.79 g-atom of lithium dispersion in vaseline (containing 2 percent Na). About 10 percent of a total of 0.18 mole of ethyl 6-chlorohexyl acetaldehyde acetal was added at room temperature under anhydrous and anaerobic conditions. The remaining chloracetal was added dropwise over a one-hour period at a temperature between 0 C. and l5 C. The mixture was stirred at 0 C. for an additional hour, then transferred by positive argon pressure to a beverage bottle and subsequently filtered in a dry box to remove the unreacted lithium metal and the lithium chloride that was formed. The amber filtrate was analyzed by the Gilman double titration method. (Total base 0.728

' M; Free base 0.55 M; percent C-Li 92.4 percent; Conc. C-Li 0.67 M). The product was ethyl 6- lithiohexyl acetaldehyde acetal.

EXAMPLE 7 PREPARATION OF ETHYL p-LITHIOPHENYL ACETALDEHYDE ACETAL EXAMPLE 8 PREPARATION OF ETHYL 3-LITI-IIOPROPYL Y ACETONE KETAL 1 Ethyl 3-bromopropyl acetone ketal as prepared in 0 Example 4 is lithiated by the procedure outlined in Example 5 to form ethyl 3-lithiopropyl acetone ketal.

EXAMPLES OF CLAIMED PROCEDURES AND PRODUCTS l. INITIATORS FOR THE POLYMERIZATION OF 'CONJUGATED DIENES AND VINYL MONOMERS AND THE COPOLYMERIZATION OF CONJU- GATED DIENES WITH ALIPHATIC OR ARO- MATIC VINYL MONOMERS.

New live polymers and copolymers are represented by the following formulae:

Acetal-R-P-Li and Ketal-R-P-Li in which (a) acetal stands for hydroxy carrier acetal,

I -0-C-R l and ketal stands for hydroxyl carrier ketal,

-0-C-R s in which R,, R and R are straight-chain or branchedchain or cycloalkyl groups of l to 3 or or or more carbon atoms or phenyl or alkyl phenyl in which each alkyl group contains 1 to 3 or more carbon atoms; it being understood that R, and R may be alkyl groups which are part of a ring, e.g. a pyranyl group; and (b) P stands for a bivalent radical ofa homopolymer or copolymer unit which includes at least two monomers, of which the following are representative:

l-lomopolymers of conjugated dienes and vinyl monomers:

Polybutadiene Polyisoprene Polypiperylene Styrene and other vinyl monomers Copolymers of conjugated dienes:

Butadiene-isoprene lsoprene-piperylene Copolymers of conjugated dienes and the following vinyl monomers:

Styrene Alpha-methyl styrene p-Chlorostyrene Vinyl pyridine Vinyl naphthalene Vinyl anthracene Acrylonitrile Methacrylonitrile Alkyl methacrylates Alkyl acrylates Vinyl sulfones Alpha-nitro oleflns and (c) R stands for a branched-chain or straight-chain or cycloalkylene group of l to 20 carbon atoms or phenylene or alkyl phenylene in which one or more alkyl substituents each contain 1 to 3 or more carbon atoms. The invention relates particularly to homopolymers and copolymers of conjugated dienes containing 4 to 6 carbon atoms and homopolymers'of vinyl monomers and copolymers of such a conjugated diene with a vinyl monomer, such as illustrated immediately above and derivatives thereof. P and R have this meaning throughout the specification.

When the polymers and copolymers are prepared with a LiR catalyst an R-polymer is formed and the expression R-polymer or R-copolymer is used in which R has the aforesaid meaning (also specifically, e.g. R- polybutadiene, etc.), when prepared by an LiR catalyst. Such catalysts include, for instance,

methyl lithium ethyl lithium butyl lithiums amyl lithiums hexyl lithiums octyl lithiums decyl lithiums allyl lithium methallyl lithium phenyl lithium xylyl lithiums tolyl lithiums naphthyl lithiums and the similar aliphatic and aromatic lithiums, known to the art as in Foster US. Pat. No. 3,464,961.

The polymerizations using the lithioalkyl acetal or lithioalkyl ketal initiators are carried out by introducing the initiator and a hydrocarbon monomer (or monomers) such as butadiene (or butadiene and styrene) into a hydrocarbon solvent such as hexane, cyclohexane or aromatic solvents such as benzene, toluduced for the polymerization. The temperature at which the polymerization is carried out may range from C. to about C., and preferably does not exceed the boiling point of the monomer at atmospheric pressure. However, it is possible to work at a temperature above the boiling point of the solvent if the monomer is sufficiently soluble in the solvent used. In general, a temperature of 0 to 50 C. is suitable. The reaction time required is dependent on the temperature and solvent employed. At 15 C. satisfactory results are obtained if the polymerization is continued for about 12 hours. Other polar solvents such as tetrahydrofuran, diethyl ether, dioxane may be employed. When the polymerization is completed, a capping agent may be employed as described in what follows.

EXAMPLE 9 POLYMERIZATION OF V BUTADIENE WITH ETHYL LITHIOALKYL ACETALDEHYDE ACE- TAL The diethyl ether solutions or hexane slurries of lithium acetal initiators, ethyl 3-lithiopropyl acetaldehyde acetal and ethyl 6-lithiohexyl acetaldehyde acetal, as prepared in Example 5 and Example 6, were used as initiators for the polymerization of butadiene. A series of runs was made using variable amounts of initiator. The recipe was as follows:

Butadiene, parts by weight 250 n-Hexane 1000 Initiator, milliequivalents Variable Time, hours l2 Temperature 15 C.

The amount of initiator is variable, depending upon the molecular weight desired (e.g. gms.monomer/eq. initiator kinetic molecular weight 171,

A butadiene-hexane blend was charged into a reactor purged with N or into baked, purged beverage bottles. The acetal-RLi initiator was added and the reactants were agitated throughout the polymerization period. Acetal-R-polybutadienyl lithium was produced- Such polymers which include a lithium metal at one end of the polymer chain and an acetal or ketal group at the other end of polymer chain are characterized by particularly narrow molecular weight distributions (MWD). MWD, hereafter will be used to designate the ratio, El /M as determined by gel permeation chromatography.

Good molecular weight control is possible with such initiators; the molecular weight of a polymer is thus dependent only on monomer and initiator charges. The preferred molecular weight range for chain-extendable liquid polymers, however, is from 60010,000.

The foregoing is illustrated of the production ofa homopolymer. Other conjugated diene monomers'may be used such as isoprene, piperylene, chlorobutadiene, etc., with other solvents usually employed in polymerizations and particularly aliphatic hydrocarbons.

The foregoing is likewise illustrative of copolymerization in which any of the foregoing-mentioned conjugated dienes and vinyl monomers are copolymerized. The amount of initiator employed will depend upon the concentrations employed and the temperatures employed may be those which are usual in copolymerization reactions. The temperature above given is illustrative and the reactions may be carried out at any usual polymerization temperature. I

Polymers and copolymers having the formula Acetalor Ketal-R-P-Li and a wide range of properties are prorinnihlp innlnrlinc flnwahle nrntlllCtS m resilient solids of higher and lower glass transition temperatures. A wide variety of products, including those mentioned in the preliminary portion of this patent application, are obtainable, and such products may be used in reactions which are described in what follows.

The lithium alkyl ketals may be used as initiators in similar reactions.

The processes and products described and mentioned in connection with Example 9 are new. 2. THE PRODUCTION OF MONOACETAL AND MONOKETAL POLYMERS AND COPOLYMERS BY TERMINATING SUCH LIVE POLYMERS AND COPOLYMERS WITH ALCOHOLS, e.g. METHA- NOL, ISOPROPANOL, ETC.

The polymers and copolymers are new. The following formula is representative of the polymers and copolymers which are produced.

3. THE PRODUCTION OF DIACETAL, DIKETAL, POLYACETAL AND POLYKETAL R-POLYMERS AND R-COPOLYMERS BY TERMINATING THE AFORESAID LIVE POLYMERS AND COPOLY- MERS WITH A DIFUNCTIONAL OR POLYFUNC' TIONAL JOINING AGENT.

The diand poly-acetal or ketal-R-polymers and -R copolymers and process for preparing the same are new. They are not anticipated by such art as NASA nol, ethanol, isopropanol, etc. The reaction can be car- 3 ried out at any temperature from C. to room temperature or above.

EXAMPLE l0 ACETAL-R-POLYBUTADIENE An excess of methanol was added to the hexane solution of live acetal-R-polybutadienyl lithium which may contain a small amount of ether as described in Example 9. The mixture separated into two layers. The methanol layer, containing lithium methoxide (a by-product of the reaction) was discarded. Antioxidant (0.5 part for every 100 parts of polymer) was added to the hexane layer, containing the polymer. The polymercontaining layer was concentrated and dried on a rotary vacuum evaporator. The molecular weight distribution and compositions of various polymers were determined, and are recorded in the following table.

The presence of the acetal end group was established by infrared analysis of the products (strong COC absorption at 8.89.5p.).

Acetal or Ketal-R-P-Si-P-R-Acetal or Ketal used as the joining agent.

The dior poly-acetal or ketal-R-polymers or -R-copolymers are usually prepared at a low temperature, and the joining agent may be added at this temperature, which may be as low as 35 C., but usually a higher temperature will be used, up to 50 C. in order to increase the speed of the reaction.

EXAMPLE 1 l DIMETHYL DI( ACETAL-R-POLYBUTADIENYL)SILANE A solution of live acetal-R-polybutadienyl lithium (0.08 mole), (prepared according to Example 9) was cooled to 0 C. A stoichiometric amount of Cl Si(CH (0.04 mole) was added incrementally to the acetal-R- TABLE 1 POLYMER MOLES MICROSTRUCTURE NO. lNlTlATOR lNlTlATOR g. BUTADIENE CONVERSION MWD Cisl.4% Trans-1.4% 1.2% T.F.7(

l A* 0.024 78.5 1.06 21.9 41.7 36.4 87.3 2 A 0.020 78.5 100 L05 16.5 44.9 38.6 90.3 3 8" 0.020 78.5 100 L07 l0.5 35.5 54.0 89.4

Ethyl ti-lithiohcxyl acetaldchydc acetal "Ethyl 3-lithiopropyl accialdchydc acclul T.F.

Empiricully determined total 7: unsuturatiun (of all microstructurcs) in the polymer.

polybutadienyl lithium with vigorous stirring. After 20 hours the mixture was allowed to warm to room temperature (28 C. An excess of n-butyllithium was then added to react with any unreacted Cl Si(CH and then the batch was dropped into an excess of methanol 5 containing 0.5 part of 2,6-di-tert.-butyl-4- methylphenol. The solvent was stripped on a rotary vacuum evaporator. Two such examples were pre- An excess of nbutyllithium was then added to react with any unreacted Cl SiCH and then the batch was dropped into an excess of methanol (containing 0.5 part DBPC). The solvent was stripped on a rotary vacuum evaporator. The polymer is characterized in Table III. The presence of acetal terminal end groups was demonstrated by strong CO C absorption (8.8-9.5;1.) in the infrared spectrum of this polymer.

TABLE III POLYMER 'I'HI-I()R E'IICAL THEORETICAL r- L: NO. EACH BRANCH IOINED WI, (GPC) MWD POLYMER 6 I500 4500 4200 Li pared. When appropriate care is exercised a good correspondence between theoretical and experimental molecular weights was realized with little or no broadening of the MWD (Table II). The presence of acetal end groups was demonstrated by IR (strong C-OC absorption 8.8-9.5u).

4. THE PRODUCTION OEMONOACE-TAL AND MONOKETAL-MONO(X) POLYMERS AND CO- 20 POLYMERS BY TERMINATING SAID LIVE POLY- MERS AND COPOLYMERS WITH SUITABLE X REAGENTS.

The polymers and copolymers are new as is the pro- 'VPO stands for Vapor Pressure Osmomcrry and GPC stands for Gel Permeation Chromatography.

When live R-polymer or R-copolymer acetals or ket- 3 als are terminated with polyfunctional joining agents,

5 cess for producing such materials. The polymers and copolymers that can be used comprise units defined above.

SiCl CH Cl CH, ocu@cn 51 01 001 etc.,

NCO

polyacetal or polyketal R-polymers or R-copolymers are formed. For example, when Cl SiCH is used as a joining agent the following formula is representative of the polymers and copolymers formed:

When live R-polymer and R-copolymer acetals and ketals are terminated with a suitable anionically reactive agent, e.g., an epoxide, an aldehyde, a ketone, carbon dioxide, carbon disulfide, sulfur, an alkyl disulfide,

Acetzal or Ketal-R-PSiPR-Aceta1 or Ketal l P I R Acetal or Ketal With differen j g ag the j g unit will, of 60 etc. and then terminated with a protic solvent, the recourse, be different, and the number of polymer or copolymer units will depend upon whether the joining agent is trifunctional, tetrafunctional, etc.

EXAMPLE l2 METHYL TRI(ACETAL-R-POLYBUTADIENYL) SILANE To 0.105 mole of acetal-R-polybutadienyl lithium (prepared according to Example 9) was added 0.035

suiting polymers are terminated at one end by an acetal or ketal moiety and by an (X) functional group at the other chain end. The termination may be carried out at any suitable temperature as, for example, 35 C. to 50 Acetal or Ketal-R--PR'-OH in which R and P have the meanings previously dewhen an epoxide is used to terminate the live acetal or ketal polymer.

EXAMPLE l3 2-(ACETAL-R-POLYBUTADIENYL) ETHANOL Butadiene was polymerized with lithium alkyl acetaldehyde acetal as described in Example 9. After removal from the polymerizer, a bottle ofthe polymer solution was cooled in dry ice. Ethylene oxide, which had been flash distilled and stored over calcium hydride, was added by double needle as a liquid (either as a stoichiometric amount or in excess) to the live polymer at dry ice temperature. The dry ice was allowed to evaporate overnight. (When a reactor is used, the ethylene oxide is added directly to the reactor at -l5 C. and reacted overnight.) There was no evidence of gelation (complexation) during the ethylene oxide reaction even when stoichiometric amounts of the epoxide are used. The temperature of the ethylene oxide reaction was varied from 78 C. to +50 C., still without gel formation. However, temperatures from 78 to +l C. generally gave the best functionality data. Antioxidant (DBPC) was added and the polymer was quenched in an excess of methanol. Usually enough methanol was added to solubilize the LiOMe, formed as by-product. The polymer solutions were concentrated on a rotary vacuum evaporator.

The reaction is represented by the following equation:

( rim polybutadiene acetals, the polymers are first com-.

pletely dissolved in a hydrocarbon medium, e.g., hexane, heptane, benzene, toluene, etc., and then a protic solvent, e.g., water, methanol, ethanol, etc., is added. The relative proportions of protic solvent and hydro carbon solvent can vary from trace amounts of protic material to a fraction of protic solvent up to but not exceeding the solubility requirements of the polymer. The preferred solvent mixtures are toluene/H O mixtures with the per cent of water varying from 0-25 per cent. The choice of the toluene/H O solvent mixture has the added advantage of relatively high binary azeotrope boiling point of 85 C. (at 1 atm.). The conversion of acetal-terminated polymers and copolymers to hy droxy-terminated polymers and copolymers requires an acid catalyst. Both inorganic (e.g, HCl) and organic acid (e.g., CH COOH, CI CHCOOH, p-toluenesulfonic acid, methane sulfonic acid, etc.) catalysts can effect the hydrolysis of the acetal moiety. However, dichloroacetic acid (Cl CHCOOH) is the acid catalyst of choice. For the toluene/H O solvent mixture, the preferred acid catalyst concentration is 0.6-1.0 gm CI CHCOOH per 100 g. polymer per 500 ml. of solvent. The hydrolysis mixture is heated while a stream Acetal or Ketal-R-P-Li Acetal or Keta1-R- P(CH OH (2) H O or ROH The presence of acetal and OH end groups was demonstrated by polymer infrared absorptions at 8.8-9.5 1. and 2.93.0p., respectively. Typical polymer characteristics are given in Table IV. Typical hydroxyl functionof nitrogen is passed through the mixture to entrain volatile by-product of the hydrolysis. I

The hydrolysis can be carried out at any suitable temperature, such as C. to 150 C., but usually beality data (Table V) quantitatively demonstrates the 40 tween and 80 C.

presence of OH end groups.

The reaction is illustrated by the following equation:

TABLE IV POLYMER MOLES MICROSTRUCTURE NO. lNlTIATOR lNlTlATOR g. BUTADlENE MWD Cis-l,47z Trans-1.4% l.27r T.F.7r

CONVERSlON 7 A* 0.021 73.5 100 1.05 17.0 37.] 45.9 88.9 8 A 0.09 I77 100 1.05 17.7 30.9 51.3 89.7 9 A 0.07 I72 100 1.05 16.8 33.3 49.8 88.7 l0 A* 0.012 70.0 lOO l.05 22.5 39.3 38.2 90.9

Ethyl fi-lithiohcxyl acetaldehyde acetal. T.F. Empirically determined total 7: unsaluralion (of all microslructurcs) in the polymer.-

TABLE v H Acetal-or Ketal-R-P-H U HO-R-P-H M, (GPC EXP. THEORY POLYMER NO. or VPO) OH meq/gm f(OH) f(OH) EXAMPLE l4 7 5686 0.18 1.07 L0 3 53 1;, .3213 3.3; pg PREPARATION OF MONOHYDROXY 10 6217 0:14 0:87 1.0 R'BUTADIENE 5. THE CONVERSION OF ACETAL AND KETAL TERMINATED R-POLYMERS AND R- COPOLYMERS TO HYDROXY-TERMINATED R- POLYMERS AND R-COPOLYMERS Acetal and ketal terminated R-polymers and R- copolymers can be converted to hydroxyl-terminated polymers by hydrolysis. The polymers and copolymers.

the mixture for the duration of the reflux to entrain the acetaldehyde as it was formed. The polymer layer was neutralized with per cent NaOH or 10 per cent Na CO and concentrated on a rotary vacuum evaporator. The analytical functionality data of monohydroxy polymers is recorded below (Table VI), the polymers being identified by the addition ofthe letter A to the numbers used in Table I, for their mono-acetal-R-polymer precursors. In other words, the hydroxy-R-polymers in Table V1 are the result of treating the three acetal R- polymers in Table 1 with CI CHCOOH as in Example 14.

Bromoand fluoro-acetic acid may be substituted for other weakly acidic chloroacids referred to herein for effecting such hydrolyses and hydrolyses such as those described in the examples, and the conditions known for hydrolysis of ketal and acetal compounds may be used.

EXAMPLE l5 Acetal or Ketal-R-P-Li TABLE V11 POLYMER M, (GPC EXP. THEORY NO. or VPO) OH meqlgm. r (OH) r1011) 5A 4037 0.47 1.119 2.0 8A 2317 0.83 1.92 20 9A 2524 0.70 1.77 2.0 10A 6147 0.32 1.97 2.0

The series of Examples 9, l 1 and 15 and the series of Examples 9, l3 and 15 set forth below, constitute novel methods of preparing dihydroxy polymers of high purity without a concomitant gel problem.

It is known in the art that the production of di- (OHR)polybutadiene polymers by the ethylene oxide termination of dilithium polymers has a great propensity to gel (S. Reed, J.Poly.Sci. A-l, 1187, 1972). A number of patents have been issued on methods of combating gel formation based on very delicate balances of stoichiometry, temperature, solvent medium, etc. (Goldberg, U.S. Pat. No. 3,055,952; H. Hsieh, U.S. Pat. No. 3,175,997; National Distillers and Chem. Corp., British Pat. No. 1,029,451.)

The advantage of the series of processes diagrammed below and involving the procedures of Examples 9, l3 and 15 is that when ethylene oxide end-capping is used to terminate the live acetal polymer there is no gel formation, independent of stoichiometry, temperature, etc.

(Example 9) (2) H 0 or ROH I [Acetal or Ketal-R-P] Si(C1'1 DIMETHYL D1(HO-R-POLYBUTAD1ENYL) SILANE and 2-(HO-R-BUTADIENYL)ETHANOL One diacetal-terminated R-polymer- (prepared according to Example 11) and three monoacetalmonohydroxy terminated R-polymers (prepared according to Example 13) were separately dissolved in a 75:25 toluenerl-l O mixture. Dichloroacetic acid (1.0 g. per 100 g. polymer per 500 ml. solvent) was added as catalyst for the hydrolysis of the terminal acetal groups, The mixtures were refluxed overnight at 75-85 C., or until there was no change in the OH-region (2.9 1.) and the COC region (8.8-9.5;1.) of the infrared spectrum of each reaction mixture. A stream of nitrogen was passed through each mixture for the duration of the reflux to entrain the acetaldehyde as it was formed. Each polymer layer was neturalized with 10 per cent Na CO and concentrated on a rotary vacuum evaporator. A sampling of data for dihydroxy terminated polymers prepared in this manner is given in Table V11. The letter A has been added to the numbers of the products to indicate that the polymers treated were Polymers No. 5 of Example 11 and Nos. 8, 9 and 10 of Example 13. Polymer No. 5A is dimethyl di(HO-Rpolybutadienyl) silane and Polymer Nos. 8A, 9A and 10A are 2-(HO-R-butadienyl) ethanol.

Acetal or Ket aL-R-P- CH CH OH (Example 13) ao-a-p-ca cn on Furthermore, the above equations illustrate that the processes described herein have an added versatility in that the troublesome ethylene oxide end-capping reaction can be avoided altogether by using suitable joining processes and acetal hydrolysis (Examples 9, ll, 15).

The equations illustrate the use of ethylene oxide, but any epoxide used for end-capping such as those previously mentioned herein may be employed, and the hydrolysis may be carried out at temperatures from 35 C. to 150 C. with temperatures of 50 C. to C. being preferred. Instead of (CH SiCl one might use CH SiCl or SiCl,,, or like alkyl compounds in which the alkyl groups contain 1 to 10 carbon atoms, or the corresponding compounds of other halogens. Thus the acetal or ketal polymer and the hydroxyl polymer derived from it may contain up to four acetal, ketal or hydroxyl repeating units, depending upon the number of chlorine atoms attached to the reactant chlorosilane. The hydrolysis is carried out by any of the aforesaid procedures, using a weak acid system.

The steps of the procedures resulting in the final production of the hydrolysis product illustrated in the equations immediately above, are illustrated in the examples, as noted, and therefore are not repeated.

EXAMPLE l6 METHYL TRI( HYDROXY-R-POLYBUTADIENYL) SILANE Triacetal terminated polymer (prepared according to Example 12), (147 gms.) was dissolved in 725 ml. of (75:25) toluenezH O. A 1.5 gms. quantity of Cl CHCOOI-I (catalyst) was added and the mixture was refluxed overnight under a steady stream of N (to entrain the acetaldehyde as it was formed). The material 'was washed with per cent K CO and H O (until neutral to litmus). The polymer was concentrated on a rotary vacuum evaporator. The following functionality data was achieved for the preparation of a trihydroxyterminated polymer (Table VIII). The letter A has been added to the number of the polymer product to indicate that the polymer treated was Polymer No. 6 of Example 12.

TABLE Vlll POLYMER M, EXP. THEORY NO. (GPC) OH meq/gm HOH) HOH) 6. CHAIN-EXTENDED HYDROLYZED TERMINAL ACETAL AND KETAL POLYMERS.

Terminal HORPROH and (HOR P-)-,A polymers and copolymers derived from Acetal or KetalRP--ROH and (Acetal or KetalR P-)- A polymers and copolymers as described herein are chain extendible by a variety of agents to form EXAMPLE 17 Polymers (prepared according to Examples 15 and 16) are chain-extended according to the following procedure:

The polymer is mixed with basic catalyst (e.g., dibutyl tin dilaurate) and may be compounded with carbon black and antioxidant or the like, together with toluene diisocyanate or other chain-extending agent disclosed herein. After the solid reactants are weighed, the mix-' ture is transferred to a three-roll paint mill and milled for 30 minutes. The paste-like product is cast into appropriate molds and allowed to reach partial gelation at room temperature before curing under pressure. The products which are formed exhibit physical properties (e.g. tensile strength, elongation, compression set, etc.) in ranges desired for elastomeric materials. If a diisocyanate, OCNR"NCO, is used as a chain-extending agent, the polymer I-IORPR'OH is thus converted to O 0 ll ll +O-R-P-R' -O-C-NH-R"NH-C']- and the polymer (HO-R-P),A is converted to In Formula I of conversion products (a) R and R stand for different straight-chain or branched-chain or cyclo-alkylene groups of l to 20 carbon atoms or phenylene or alkyl phenylene in which each alkyl group contains 1 to 3 carbon atoms, (b) P stands for homopolymer or copolymer of a conjugated diene of 4 to 6 carbon atoms or homopolymer of a vinyl monomer or a copolymer of such a conjugated diene and a vinyl monomer and (c) y is a whole number which represents the number of repeating urethane units in the polymer, and (d) R" stands for a straightor branched-chain, or cyclo-alkylene, phenylene or alkyl phenylene residue from the diisocyanate, OCNR"NCO.

In Formula II of conversion products (a) R stands for a straight-chain or branched-chain or cyclo-alkylene group of l to 20 carbon atoms or phenylene or alkyl phenylene in which eachalkyl group contains 1 to 3 carbon atoms, (b) P stands for a homopolymer or copolymer of a conjugated diene of 4 to 6 carbon atoms or a homopolymer of a vinyl monomer or a copolymer of such a conjugated diene and a vinyl monomer, (c) A stands for a joining-agent residue, (d) x is a whole number less than or equal to the valence of the joiningagent residue, (e) R" stands for a straight-chain, or branched-chain, or cyclo-alkylene, phenylene, or alkyl phenylene residue from the diisocyanate, OC- NR"NCO, and (f) y is a whole number which represents the numberof repeating urethane units in the polymer, it being understood that when x 2, Formula II has the linear repeating units and when x is greater than 2, Formula II has branched or network repeating units. For example, when x 3, the formula is 1. Lithium-terminated homopolymers and copolymers of conjugated dienes and copolymers of conjugated dienes and copolymersof conjugated dienes and styrene terminated with an aliphatic acetal or ketal group which is an hydroxyl carrier, the content of the vinyl configuration of the repeating conjugated diene units being substantially 36.4 to 54.0 per cent.

2. Lithium-terminated homopolymers and copolymers of conjugated dienes containing 4 to 6 carbon atoms and copolymers of such dienes and styrene terminated with an aliphatic acetal or ketal group which is an hydroxyl carrier, the content of the vinyl configuration of the repeating conjugated diene units being substantially 36.4 to 54.0 per cent.

3. Lithium-terminated homopolymers of conjugated dienes containing 4 to, 6 carbon atoms terminated with an aliphatic acetal or ketal group which is an hydroxyl carrier, the content of the vinyl configuration of the re- 21 peating conjugated diene units being substantially 36.4 to 54.0 per cent.

4. Lithium-terminated polybutadiene terminated with a Cl)C H -O-CHCH group, the vinyl content of the repeating butadiene units being substantially 36.4 to 54.0 per cent.

5. The improvement in the process of producing polymeric materials which comprises (a) polymerizing or copolymerizing conjugated dienes containing 4 to 6 carbon atoms or (b) copolymerizing such a conjugated diene and styrene, which improvement comprises reacting such monomer in the presence of an initiator of the class consisting of a compound of the formula:

in which Li stands for lithium, R is a branchedor straight-chain or cyclo-alkylene group of l to carbon atoms and R R and R are hydrocarbon aliphatic substituents, the content of the l,2-configuration of the repeating conjugated diene units being substantially 36.4 to 54.0 per cent.

6. The improvement in the process of producing polymeric materials which comprises (a) polymerizing or copolymerizing conjugated dienes of 4 to 6 carbon atoms or (b) copolymerizing such a conjugated diene and styrene, which improvement comprises reacting such monomers in the presence of an initiator of the class consisting of a compound of the formula OR OR Li-R -OC-R 8. The process of claim 6 in which the initiator has the formula Li-R -0-C-R 9. Polymers and copolymers of the formula Hydrocarbon aliphatic acetal or ketal-R-P-H in which P stands for a homopolymer or copolymer of a conjugated diene of 4 to 6 carbon atoms, or a copolymer of such a conjugated diene and styrene, and R stands for a straight-chain or a branched-chain or a cycloalkylene group of l to 20 carbon atoms and the acetal or ketal group is an hydroxyl carrier.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3:862AOO Dated January 21 975 Inventor(s) Adel Farhan Halasa and Donald Norman Schulz It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the second column of the "Abstract", Line 9, "Cl SICH should read ClSiCH In Column 2, Line '18, "-CSSH-" should read CSSH In Column 9, Line 44, after "ll-polymer" insert or copolymer In Column '10, Line 55, after "liquid" insert. polyene i In Column 14, Line 64, "55 C." should read -55 C.

In Column '16, Line 4, "Rcopolymers" should read R-copol ymers In Column '17, Line 44, under HO-R-P Si(CH insert (Example 15) In Column '18, Line 44, under "HO-R-P-CH CH OH" insert (Example 15) In Column 22, Claim 6, Line 5, in the second formula "Li R C-C42 should read LiR, OCR5 Signed and sealed this 6th day of May 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer I and Trademarks 

2. Lithium-terminated homopolymers and copolymers of conjugated dienes containing 4 to 6 carbon atoms and copolymers of such dienes and styrene terminated with an aliphatic acetal or ketal group which is an hydroxyl carrier, the content of the vinyl configuration of the repeating conjugated diene units being substantially 36.4 to 54.0 per cent.
 3. Lithium-terminated homopolymers of conjugated dienes containing 4 to 6 carbon atoms terminated with an aliphatic acetal or ketal group which is an hydroxyl carrier, the content of the vinyl configuration of the repeating conjugated diene units being substantially 36.4 to 54.0 per cent.
 4. Lithium-terminated polybutadiene terminated with a
 5. The improvement in the process of producing polymeric materials which comprises (a) polymerizing or copolymerizing conjugated dienes containing 4 to 6 carbon atoms or (b) copolymerizing such a conjugated diene and styrene, which improvement comprises reacting such monomer in the presence of an initiator of the class consisting of a compound of the formula:
 6. The improvement in the process of producing polymeric materials which comprises (a) polymerizing or copolymerizing conjugated dienes of 4 to 6 carbon atoms or (b) copolymerizing such a conjugated diene and styrene, which improvement comprises reacting such monomers in the presence of an initiator of the class consisting of a compound of the formula
 7. The process of claim 6 in which the initiator has the formula
 8. The process of claim 6 in which the initiator has the formula
 9. Polymers and copolymers of the formula Hydrocarbon aliphatic acetal or ketal-R-P-H in which P stands for a homopolymer or copolymer of a conjugated diene of 4 to 6 carbon atoms, or a copolymer of such a conjugated diene and styrene, and R stands for a straight-chain or a branched-chain or a cycloalkylene group of 1 to 20 carbon atoms and the acetal or ketal grOup is an hydroxyl carrier. 